Measurement Methodology of Deformation of Fiber Reinforced Polymer Composite
Plates Under Uniform Static and Dynamic Loading
Isaac Pinsky, Class of 2014, Mechanical Engineering
Abstract
Mentor: Feridun Delale, Chairman of M.E. Department
Methods
Results
Summary
Pressure Cycling of Composite Plate
Introduction
Fiber reinforced polymer composite materials are rising in
popularity in structural applications. Their combined
properties of light weight and high strength, stiffness, and
energy absorption make them ideal for use air and
ground vehicles. The challenge that arises when designing
these materials is to maximize certain properties, or to
combine the materials in a way that produces a desired
property for a specific application. The variables involved
with this type of heterogeneous material include the type
of polymer or matrix, the types of fibers, matrix-fiber
interface, laminate interface, laminate orientation, and
lay-up sequencing. The examination of these properties in
response to static and dynamics loadings is needed to
understand composite material performance in structural
applications.
600
500
Pressure [kPa]
The large scale high resolution shock tube in the City
College of New York’s facility was used to produce both the
static and dynamic loadings on the test plates. A pressure
transducer installed a short distance from the end of the
shock tube measured the pressure in the tube.
A laser micrometer was used for all static loading test and
some dynamic loading tests. For some static loading tests the
laser micrometer was attached to a sliding mechanism with a
built-in infrared position sensor to record the position of the
laser micrometer as it moved across the diameter of the
plate. The static loading was produced by connecting an air
compression system to the shock tube. Pressure in the tube
was measured on an analog pressure gage during the tests.
The data from the pressure transducer, laser micrometer, and
infrared sensor were all recorded by a single computer with
custom data acquisition software.
The dynamic loading tests were performed using a shock
wave produced by the shock tube. Shockwaves were
produced in the shock tube by sealing off the high pressure
chamber at the end of the shock tube with an aluminum
diaphragm designed to fail in a certain range of pressures.
The high pressure chamber was then pressurized until the
diaphragm failed, causing a shockwave to travel down the
shock tube and into the test plate installed in the end cap.
The deformation of the plate as a result of the dynamic
loading from the shockwave was measured using timeresolved catadioptric stereo digital image correlation or TRCSDIC, that allowed for measurement of both in-plane out-ofplane deformations. This method consists of a high-speed
camera and a system of mirror to produce stereo images of
the test plates for the camera to record.
400
300
200
100
138 kPa
275 kPa
414 kPa
552 kPa
689 kPa
0
-100
-0.5
0
0.5
1
1.5
2
2.5
Displacement [mm]
3
3.5
4
4.5
15
0 kPa
34 kPa
0 kPa
69 kPa
0 kPa
103 kPa
0 kPa
138 kPa
0 kPa
207 kPa
0 kPa
275 kPa
0 kPa
414 kPa
0 kPa
552 kPa
0 kPa
689 kPa
0 kPa
827 kPa
0 kPa
10
5
0
0
50
100
150
200
250
300
Transverse position [mm]
Figure 4: Results of a pressure cycling recorded using the
laser micrometer on its sliding mechanism.
1
2
3
4
5
6
7
8
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
Figure 5: Results of a dynamic loading test on an aluminum plate
recorded using TRC-SDIC (Interval of 0.13 ms)
Figure 1: The working end of the shock tube with the laser micrometer in
place. The black markings on the plate are used for TRC-SDIC
1
2
3
4
5
6
7
8
9
Shock tube
Shock wave
Pressure
transducer
W
s
Primary
Steel plate
?
Primary
Mirror A
Secondary
mirror A
Triggering
signal
Secondary
mirror B
Mirror B
Phantom
High speed
camera
Figure 2: The experimental setup for a dynamic loading test using
TRC-SDIC
The two methods of measuring the deformation of fiber
reinforced polymer composite plates have proven to be
very effective. The laser micrometer and sliding
mechanism allow plastic deformation of the plates to be
displayed easily in graphical format. The time resolved
catadioptric stereo digital image correlation method is a
robust method capable providing displacement data in X,
Y, and Z directions, but X and Y direction could not be
shown. It is hoped that these methods will be used in the
experimental testing of fiber reinforced polymer
composites with additives.
Figure 3: These displacement results of the pressure cycling of a composite
plate were produced by aiming the micrometer at the center of the plate.
Plate deformation [mm]
Due to the many parameters involved in the manufacture
and composition of composite materials, their
characteristic properties are difficult to analyze and
extensive testing is required to obtain both qualitative
and quantitative data. A standard testing methodology
was developed to measure plastic deformation in fiber
reinforced polymer composite plates under uniform static
and dynamic loadings. Both static and dynamic loadings
were produced using CCNY’s large-scale high-resolution
shock tube facility. The plastic deformations produced in
static tests were measured using a laser micrometer with
a custom-built sliding mechanism. A pressure transducer
was used to measure the loadings that were then
correlated with the displacement of the test plates. The
plastic deformations produced in the dynamic tests were
measured using time-resolved catadioptric stereo digital
image correlation with a high speed camera and a simple
mirror setup. Steel and aluminum plates were tested for
use as a baseline comparison. The static load testing
method resulted in consistent experimental data. These
results altered slightly from plate theory due to a lack of
zero-slope at the plate boundary. The dynamic load
testing method also resulted in consistent data, but with a
slight variations from the inherent symmetry of
experimental setup.
700
Figure 6: Results of a dynamic loading test on a composite plate
recorded using TRC-SDIC (Interval of 0.13 ms)
References
Jahnke, D. (2013). The Effect of Shockwave Impingement on
Composite Plates with Nano Additives. New York, New York:
City College of New York, Mechanical Engineering Dep.
Acknowledgments
I would like to thank Professor Feridun Delale for allowing
me to participate in this research project, and graduate
student Doug Jahnke for all he has taught me about
experimental research in composite materials.
Student Profile
Isaac Pinsky is a senior working on his degree in
Mechanical Engineering at The City College of New York.
Before he began his academic career at CCNY he
completed two years in a Jewish seminary program at The
Rabbinical College of America in Morristown, New Jersey.
Once he gained a secure foundation in his Jewish heritage
he focused on a career in mechanical engineering. After
completing his bachelor’s degree, he plans to work in the
power generation industry as a mechanical engineer.
Isaac Pinsky chose to do research in materials science to
further expand his knowledge and experience in different
engineering fields. He began work with a group of
graduate students under the mentorship of Prof. Delale to
study the properties of fiberglass composites with
additives. Isaac Pinsky has strong ties with the American
Society of Mechanical Engineers Student Section at CCNY,
and served as secretary and executive board member for
the section during his junior year.